Pope Francis admitted for the first time Tuesday that nuns have been sexually abused by priests and bishops in the Catholic Church — and even held as sexual slaves.

In one case, the abuse was so serious that an entire congregation of nuns was dissolved by former Pope Benedict, CBS News reported.

“There are some priests and also bishops who have done it,” the pontiff told a reporter during his return flight from the United Arab Emirates, where he held the first-ever papal Mass in Abu Dhabi.

His admission followed a rare outcry last week from the Vatican’s monthly magazine Women’s Church World over the sexual abuse of nuns and religious sisters feeling forced to undergo abortions or raise kids not recognized by their fathers.

The February edition included the pope’s own take on the scandal — which the Vatican has long known about — in which he blamed the unchecked power wielded by priests and higher clergy for the crimes.

Francis conceded on his flight Tuesday that it was a problem and said more action was needed — insisting that the will to confront the abuse was present.

“It’s a path that we’ve been on. Pope Benedict had the courage to dissolve a female congregation which was at a certain level, because this slavery of women had entered it — slavery, even to the point of sexual slavery — on the part of clerics or the founder,” he said.

A Vatican spokesman confirmed to CBS News that the order of nuns dissolved under Benedict was the Community of St. Jean in France.

The Saint Jean order was dissolved in 2005, the first year Benedict served as pope, though the reason it was disbanded had not previously been made public.

“I would like to underscore that he was a man who had the courage to do many things on this topic,” Francis said of his predecessor, who stepped down in 2013.

The pope said the problem only existed in “certain congregations, predominantly new ones and in certain regions more than others.”

He said the Catholic Church “shouldn’t be scandalized by this,” adding that “there are steps in a process,” and “we are working on it.”